BEIJING — The dramatic ouster of Bo Xilai as Communist Party chief in Chongqing has prompted an outpouring from people who say their relatives were wrongly jailed under his rule and want the government to reopen their cases.

More than 4,000 people were jailed during an aggressive anti-crime campaign that Bo launched in late 2007. While Bo insisted that he was cracking down on gangsters and lawlessness, critics say he led a brutal effort designed to punish rivals and squeeze money from local businesses.

How the government handles the myriad cases and the mounting evidence of wrongdoing poses yet another test for a Chinese leadership that is anxious to contain the growing scandal, but that also claims to be publicly committed to upholding the rule of law.

Many of the relatives have been making the trek from the southwestern interior city of Chongqing to the home of Li Zhuang, a prominent Beijing lawyer, who they hope can help them get justice for their relatives languishing in jails back home. Most come secretly, and do not want themselves or their relatives to be identified for fear of retribution.

“My place has become the petitioning office for Chongqing people,” said Li, who was receiving a steady stream of visitors on a recent morning. “They know I am against what Bo Xilai did in Chongqing.”

Before his sudden fall last month, Bo was a charismatic rising star in China’s opaque political system. His ascent was disrupted by a wide-ranging corruption and murder probe that has already snared his wife, a household aide and a number of his top associates. Bo’s removal, and the ensuing investigation into the murder of British businessman Neil Heywood, has embroiled China’s Communist Party in its worst internal strife since the 1989 crackdown on pro-democracy demonstrators in Tiananmen Square.

In Chongqing, Bo was perhaps best known for leading a ferocious assault on crime called “da hei,” or “strike the black,” that was led by his right-hand man, the former police chief Wang Lijun, who later betrayed him.

The thousands jailed in the campaign, also called “hard strike” in the Chinese media, included gang members, wealthy businessmen, police officers and local government officials. About 1,000 people were sentenced to forced labor, and dozens executed, many after hasty trials that ignored even rudimentary judicial procedures. Many have alleged that they were tortured while in custody and confessed under duress.

Li, the lawyer, listens to the relatives’ stories and gives them advice where he can. But he tells them he is not in a position to offer legal services. In fact, he was one of the victims and is trying to have his own conviction overturned.

Li went to Chongqing in 2009 at the request of family members of Gong Gangmo, who ran a motorbike company and was accused of being part of a criminal syndicate. But Gong told the court that Li encouraged him to lie and to claim he was tortured — so Li was then arrested and jailed for 18 months after a quick trial and despite his protestations of innocence.

Li was released in June 2011, after his case sparked a national outcry about the breakdown of law and order in Chongqing, where even lawyers could be arrested for defending their clients.

A ‘sensitive’ topic

Since the Bo scandal erupted, China’s Communist rulers have been trying to allay widespread suspicions that he was removed for political reasons ahead of this year’s leadership change. “This criminal case shall not be interpreted as a political struggle,” said an official editorial Thursday by Xinhua, the state news agency. “China is a socialist country based on the rule of law, and the sanctity and authority of that law shall not be trampled upon.”

One way for officials to show they really are concerned with the law, critics say, would be to reopen all the criminal cases in Chong-qing under Bo’s nearly five-year tenure, and not just investigate the case of the deceased Briton.

So far, however, China’s Communist authorities have shown no desire to revisit the anti-crime campaign and the cases of thousands still imprisoned.

On April 17, another lawyer, Liu Yang, published an open letter online, calling for lawyers to join him in reviewing criminal cases in Chongqing. “I received many calls for help, and I felt we needed to do something for the country, the people and for Chongqing, too,” Liu wrote. He said 26 lawyers had offered to join him.

But Liu said he was called in Thursday before the Beijing Bureau of Legal Affairs and told to desist. After his morning meeting, he declined to answer any more questions, saying the topic had become too “sensitive.”

Seizures of assets

Among those caught in Bo’s sweep were the former top judicial official in the city, Wen Qiang, who was executed in July 2010 for corruption, and Xie Caiping, known as the “Godmother of Chongqing” for her illicit gambling dens and rumorsstable of 16 lovers.

But also swept up were virtually all of Chongqing’s top businessmen, whose family members say they had no connection to criminal activity; rather, they say, the businessmen were targeted so their assets could be seized.

Among them was Wang Tianlun, a wealthy businessman with the Jinpu Food Company, who received a death sentence that was suspended, and was forced to pay a fine of 100 million renminbi. Family members said all of Wang’s assets have been frozen.

Lawyer Chi Susheng, who was hired by Wang’s family members, said she is dealing with three cases in Chongqing involving 50 people, and believes many innocent people are still jailed in the city. “I’ve been working in the criminal law field since 1979,” she said, “but I have seldom found cases dealt with like they were in Chongqing.”

Scores of police officers were also jailed for alleged corruption during Bo’s campaign. But their family members maintain that the policemen, too, are innocent, and that the real goal was to remove officers believed loyal to the previous local administration.

In one example, a decorated 50-year-old policeman with 30 years of experience was arrested in May 2010 for supposedly conniving with one of the jailed businessmen and taking bribes. He was sentenced to 17 years in prison, where he remains. His wife — who asked that neither she nor her husband be named — said, “They fabricated this.”

The woman, who is trying to have her husband’s case reopened, sobbed when she described how he was tortured to confess and lost nearly 50 pounds. “I couldn’t even recognize him,” she said. Asked how she took the news of Bo Xilai’s downfall, she laughed and said, “You can tell from my laughter. I won’t say anything in words.”

The Chongqing court could in theory reopen any case at any time; in reality, such a politically laden decision would only be made at the most senior level of the Communist Party. Li Zhuang said he is not optimistic because the sheer number of cases is too big.

In a brief interview last July in Chongqing, Bo defended his anti-crime crackdown, saying he found a lawless place when he arrived as party secretary in 2007. “It didn’t just occur to me to crack down on the triads,” he said. “It’s because when I arrived in Chongqing, the triad gangsters were here first. All governments in the world would do the same thing.”

Bo added, “If there are any illegal or mafia-related problems — someone breaking the law — we will crack down.”

Researchers Wang Juan in Shanghai and Zhang Jie in Beijing contributed to this report.